Heatsoak issues.

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Jul 19, 2006 | 09:51 AM

samgm2

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Heatsoak issues.

I have a mazda miata (1990) with an LS6/4L60E.

It's been pretty hot lately and after even mild spirited driving, I am getting boilover after I shut the engine off (3-4 minutes after engine is shut off).

I am wondering if maybe I have the fan relay wired incorrectly.

On a vette or a camaro, does the fan run after the engine is shut off?

I am using a Trans Am PCM. The fan power is tapped off the ignition power. Should it be tapped off of the battery?

Also, my intake air temperature is about 145 F at idle at 75F ambient in the evening. That seems awfully high. How does this compare with a Trans Am/Corvette/Camaro?

Thanks,

Sam

Jul 19, 2006 | 10:41 AM

PREDATOR-Z

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From: BFE

Fans are PCM managed so when motor is off so are the fans. You could put a thermo-controler on your setup to run after motor is off.
Are you runing enough coolant mix?

Jul 19, 2006 | 10:44 AM

Gearhead1

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On my '98, my tuner has it set up to where the fans run even after the engine is shut off. Of course, that's if the engine temp is high enough.

Jul 19, 2006 | 10:59 AM

samgm2

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Quote:

Originally Posted by PREDATOR-Z

Fans are PCM managed so when motor is off so are the fans. You could put a thermo-controler on your setup to run after motor is off.
Are you runing enough coolant mix?

That is probably what I will have to do.

I am running about 30/70 mix for the summer.

Is it possible my themostat has gone bad?

What should the temperature hold at on most of these cars?

Sam.

Jul 19, 2006 | 11:32 AM

white2001s10

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Definately have your radiator cap checked.
Boilover usually means loss of pressure in the system.

Jul 19, 2006 | 12:35 PM

samgm2

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Quote:

Originally Posted by white2001s10

Definately have your radiator cap checked.
Boilover usually means loss of pressure in the system.

That was the first thing I replaced. I just replaced my thermostat. Hopefully that will resolve the problem.

Sam

Jul 19, 2006 | 02:35 PM

Gearhead1

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It may just be that the engine bay is so confined that the heat has nowhere to go. It might be necessary to find a way to vent the excess heat.

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Jul 19, 2006 | 08:55 PM

samgm2

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Quote:

Originally Posted by white2001s10

maybe it's losing pressure somewhere else ...even a headgasket.

I replaced the thermostat earlier today and haven't had any problems since. It was about 100 degrees and I was in traffic. Seems to be O.K. now.

I think I will add some louvers to the hood to bring the underhood temps down. Its just too hot under there.

Thanks for all the advice.

Sam

Jul 20, 2006 | 06:31 AM

#10

PREDATOR-Z

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From: BFE

Good, that thing must fly.
What is the Miata's weight?

Jul 21, 2006 | 09:21 AM

#11

samgm2

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Quote:

Originally Posted by PREDATOR-Z

Good, that thing must fly.
What is the Miata's weight?

It gained a bit more weight than you would expect, because I didn't want the weak rear end that miata had. I went with a 2003 Lincoln LS rear end assembly.

Weight numbers:

Front 1400 Pounds
Rear 1240 Pounds (Full tank of gas)

Total 2640

Weight distribution 53/47

As far as how well it moves, it moves reasonably well for a rear wheel drive car. I put a TCI streetfighter torque converter in (probably a mistake). I am not able to apply only about 50% throttle before lighting up the rear end.

Even so, with street tires (using a Gtech Accelerometer / Pro) It records about 0-60 in 4.7 seconds. (I am not a very good driver and simply haven't gotten very good at applying the right amount of throttle - too much and its all over with a pretty lousy time - too little and I am not pushing is as much as I can).

I have no idea what it will do in the quarter mile.

I am planning on going to the track next wednesday to find out.

Sam